This invention is generally directed to a novel anchor device or fastening member which is particularly suited for use in the attachment of various fixtures and equipment to masonry, concrete, and other hard and/or friable substrates.
The prior art in one-piece, masonry tapping fasteners have uniform thread forms throughout the entire length of the fastener. They are typically heat treated to a case hardened metallurgical structure. These masonry tapping fasteners have failed for a variety of reasons, such as stripping out during the installation process, brittle failure while resisting the applied loads, and premature failure due to embrittlement and stress corrosion. As a result, users of these fasteners have been required to use other styles of fasteners that have exhibited better load versus displacement characteristics than that of a masonry tapping fasteners. These fasteners also back out of the substrate with relative ease in applications involving dynamic loads and system vibrations.
The present invention provides an anchor device or fastening member which overcomes the problems presented in the prior art and which provides additional advantages over the prior art, such advantages will become clear upon a reading of the attached specification in combination with a study of the drawings.